Charles hscher



Jan. 27, 1931. c. FISCHER DUPLEX FLEXIBLE SUPPORTING ARM Filed Feb. 1o.192s QTL,

' INVENTOR m 9M YW a /ff f AT TORNEY .0 In order to provide a PatentedJan. 27, 193.1

UNITED STATES CHARLES FISCHER, OF NEW YORK, N. Y.

DUPLEX FLEXIBLE SUPPORTING ABH Application led February 10, 1928. SerialNo. 253,245.

My invention relates to flexible supporting arms for supportin electriclamps and, more particularly, to a uplex, stiff, flexible suporting arm,which is adapted to support a ea object, such as a lamp or the like andin w ich the outer casin consists of a ilexible, spiral spring provi edwith a compensating compression spring, which will oi'er substantialresistance to flexing and which is thus enabled to adjustably support aheavy lamp. The expansion and contraction of the spiral spring as thearm is bent and returned, is compensated for and taken up by Ithecompensating spring.

One of the objects of my invention is to provide a duplex, lexible'armconsisting of a flexible core, a closely wound, spiral spring ofrectangularcross-section, surrounding the core and a compensating springad'acent to one end of the spiral spring, the sai arm -being thus adated to be adjusted into several positions an to support a heavy lamp.

With the above and other objects in view,

my invention consists in the parts, improvements and combinations morefully pointed out hereinafter.

Turning now to the drawings:

Figure 1 is a side elevation of the duplex,

flexible arm, showing the arm in place when 80 su porting a heavy lamp.

igure 2, is a side elevation of the arm showing in full lines the armbent in lampsupporting position, at the same time showing in dottedlines, the arm when straightened and also in an intermediate position.

Figure 3, is a longitudinal, transverse section through the arm, and

Figure 4, is a detail view, partly in section, of one end Yof anotherform of arm.

A exible core 1, preferably made of metal, is provided, whose ends,respectively, pass within andare secured to sleeves 2 and 3. The sleevesare provided, respectively, with shoulders 4, 5, and with skirt portions6, 7, so that the sleeves may be driven over the ends of the core 1,making a friction t between the vcore and sleeves until the ends/of thecore abut against the respective shoulders 4, 5, of sleeves 2, 3.

flexible arm which will support a heavy load and which can be easilyilexed, adjusted and bent into any of several supporting positions for aheavy lamp, I provide a closely wound, spiral spring 8, of rectangularcross-section, which sprmg surrounds the core 1. A compensatingcompression spring 9 of shorter length than the spiral spring, isarranged adjacent to one end of the rectangular spring 8, and mayconsist either of a separate spring, as shown in Figure 3, or may be anintegral portion of the rectangular spring 8, as shown in Figure 4.

As Shown in Figures 3 and 4, the coils of the compensating spring areloosel wound and further apart than the coils o the rectangular spring8, so as to make the compensating spring more compressible and`resilient.

As shown in Figure 4, the compensating spring 10, is an integralprolongation of the rectangular spring 8, and surrounds the sleeve 3,into which the flexible core projects.

In order to place the rectangular and compensating springs undercompression ,and thereby lncrease their resistance to flexing, so as tosupport a heavier load, one end of the compensating spring abuts againstan abutment, such as a collar 11, formed on the sleeve 3, and the outerend of the rectangular spring 8, abuts against an adjustable collar 12,which can be screwed 'ont the screw threaded portion 13 of sleeve 2. Byscrewin or unscrewing the collar 12, the flat spiral spring and thecompensating spring can be laced under more or less compression. y thismeans the desired range of flexion or bending of the arm can bemaintained with lamps ofadiiferent weights.

The core of the arm is hollow so as to receive an electric cable 15, inwhich the wires are placed for supplying the current to the lamp, thecable entering the sleeve 2, through opening 16.

The lamp 20, is secured to one end of the arm by the screw-threadedportion 14, the other end of the arm being mounted on a verticallyadjustable post 21, supported in a tube 22, on base 23. The post 21, maybe adjustably secured by screw 24, and the arm may be exed and set inposition by handle 25.

Having thus described the invention, its operation will be clear. Itwill be understood that changes may be made in carrying the inventioninto effect, without departing from the principle of the invention.

What I claim is:

1. A duplex fiexible supporting arm for sup orting a heavy objectcomprising in com ination, a hollow, liexible core, a spiral, exionspring surrounding said core, and a compensating compression sprlng ofshorter length than said spiral spring adjacent to one end of saidspiral spring, which compensates for the expansion and contraction ofthe spiral spring when the arm is bent.

2. A duplex flexible supporting arm for sup orting a heavy objectcomprising in com ination, a hollow, iexible core, a spiral, iexionspring of rectangular cross-section surrounding said core, a shortcompensating compression spring of shorter length than said spiralspring adjacent to the end of said spiral spring, an abutment for saidcompensating sprin a hollow sleeve into which one end of the exible coreprojects, the exterior of the outer end of said sleeve beinscrew-threaded and a nut mounted on sai screw-threaded exterior of thesleeve, and adapted to engage one end of said spiral spring so as tocompress it.

3. A duplex flexible supporting arm for supporting a heav objectcomprising in combination, a lexi le core, a spiral, iiexion spring ofrectangular cross-section surrounding said core, a short compensatingcompression spring of shorter length than said spiral spring adjacent tothe end of said spiral sprin a hollow sleeve into which one end of theexible core rojects, the exterior of the outer end of said) sleeve beingscrewthreaded, a nut mounted on said screwthreaded exterior of thesleeve and adapted to engage one end of said spiral spring so as tocompress it, and another hollow sleeve into which the other end of saidcore projects and about which the compensating spring is wound, saidlast named hollow sleeve being provided with a collar forming anabutment for the compensating sprin In testimony whereof, I name to thisspecification.

CHARLES FISCHER.

gave signed my

